- Rename --skip-snapshot-checksum to --verify-snapshot-checksum to
  avoid double negations in most of the code
- Conditionally create and verify checksums in SerializedCodeData
- Remove unused Deserializer::GetChecksum

Bug: chromium:1270752
Change-Id: I8360e0dd5f25dac68bf68909155771b302184a4b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3284883
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77925}